Apparatus for operating the points of railways, tramways, and the like.



H. A. THOMSON.

APPARATUS FOR OPERATING THE POINTS OF RAILWAYS, 'IRAMWAYS, AND THE LIKE.

APPLICATION FILED MAR. 29, 1913.

1,089,987. Patented Mar. 10, 19m

UN l1 SAEi-EBATENT UFFECE.

HUG-H ALEXANDER THOMSON, OF GLASGOW, SCOTLAND.

APPARATUS FOR OPERATING THE POINTS OF RAILWAYS, TRAMWAYS, AND THE LIKE.

Specification of Letters Patent.

Patented Mar. 10, 191st.

AppIication filed March 29, 1913. Serial No. 757,667.

To all whom it may concern Be it known that I, I'IUGH ALEXANDER THOMSON, a subject of the King of Great Britain and Ireland, residing at Glasgow, Scotland, have invented Improvements in and Relating to Apparatus for Operating the Points 01 Railways and T 'amways and the like, of which the following is a specification.

This invention relates more particularly to that kind of apparatus for operating railway and tramway and like points wherein means, such as a spring or a weight, (hereinafter sometimes referred to as a load) and other members are combined to throw the points and securely hold them in their opposite set positions when operated or reversed by being trailed through.

In apparatus of the character referred to, and especially in trail shunting operations, when a vehicle creeps along the blades, forces them partly open and returns, there is a tendency to leave the switch mechanism at its dead center of movement and the points at halt cock or partly open, thereby causing liability of derailment, to obviate which it has been proposed to employ tumbling devices embodying shitting weights whereby the parts are unable to remain in the position producing this dead center. The line of action of the load in these devices is constantly varying.

The object of the present invention is to overcome this defect of partly open or hall cock switch blades in a better way for which purpose it is arranged that the points shall be movable from one set position to the opposite set position, under a load acting against and through articulated link mechanism which, to facilitate description, is termed centerless meaning thereby mechanism the parts of which are positively constrained to follow paths such that they can never be caused to occupy a position where, were they purposely arrested, the load would not produce a turning effort on some part of the mechanism, so that the latter as a whole has no dead center but serves either to return the switch blade to initial position, when the applied movement etlort opposing the load ceases, or to continue the movement of the blade to its opposite extreme position.

The feature of the invention consists in the provision of arrangements in which continued movement of the blades, after a predetermined position is reached, is brought about by an abrupt alteration in the angular relationship of the parts as will hereinafter appear.

The accompanying drawings illustrate five arrangements for carrying out the invention, Figure 1 being a plan of one arrangement in position corresponding to one set position ot points. Fig. 2 is a corresponding view showing the position occupied by the parts when the points have been reversed. Fig. 3 is a similar view 01 another arrangement. Fig. l is a plan, partly in section, of a constructional lorm ol? spring toggle arrangement according to the invention and Fig. 5 is a sectional elevation of the same. 6 and 7 are views similar to Fig. l of modifications.

As shown in the said drawings, 1 is the device to be moved. The device 1 may be a plain lover, a bell crank lever, double cranked lever 01' frame, or a reciprocating rod, Figs. 1 and 2 illustrating a cruciform frame, Figs. and 0 a double armed lever and Figs. l and a skeleton plate frame each working on a pivot pin 2. 111 Fig. 7 the device It is a point. rod. The frame 1, Figs. 1 and 2, is amply provided with holes for connecting purposes, 3 being a slot in one arm for connection to some such member as a switch tie bar of the points and 4: being holes drilled in two other arms for a similar purpose.

5 is a toggle arm fulcrumed to rock on a pin (5 between two stops 7 and 7 on the frame. One end of a link 8 is pivotally joined at 8 to the toggle arm 5 while its other end is pin connected to a pressure rod E) pulling in a direction radial to the axis of the pivot pin 2 as indicated by the arrow head. AP represents the line passing through the axis of the pivot pin 2 with which the center line (J 1) of the frame 1 alines when the points are half thrown or in mid travel position. It is this position that ordinarily, were the connection with the rod 9 made through a usual toggle arrangement, there would be a dead center with a consequent. liability of the switch blades to stick when moving from one set normal position to the other. In the arrangement described however, when the parts are in the position mentioned, the pivotal joint 8 is to one side of the center line A B.

The operation is as followsz Assuming the parts to be in the position shown in Fig.

1, then, the center line C D of the frame being oblique to the line A B, the pull exerted on the link 8 by the pressure rod 9, through say a weight, spring or other resisting member, will act to hold the points in the set ho-me position. With movement of the points, the frame 1 turns in a clockwise direction but it will be found that wnereas the line C D comes into alinement with the line A B when the points are in mid position, the resistance leverage of the link 8 still acts to one side of the pin 2 and the toggle arm 5 and link 8 have not become superposed to produce a dead center. When the said toggle arm 5 and link 8 ultimately become superposed, the line C D will have passed out of alinement with the line A. B so that there is still an effort to return the parts to starting position. When, however, the link 8 passes the toggle arm 5, both fly over to act on the other side of the pivot pin 2, as shown in Fig. 2, the toggle arm 5 then abutting against the stop 7, and the switch blades being retained in their reverse home position. In passing over as just explained, the toggle arm 5 will be superposed upon the line C D, but then the line C D will still be so inclined to the line A B that the tog- .gle arm 5 can turn under the action of the link 8. While there is thus a dead center again as between the crank frame 1 and the toggle arm 5, there is no dead center of the mechanism as a whole.

In Fig. 3 an arm 10 of the lever 1 engages a bell crank lever 11 associated with the points, the pressure rod 9 being subjected to a thrust in lieu of a pull. The act-ion however is equivalent to that already de scribed.

To convert the mechanism to work as a one way switch of ordinary character, a hole 12 is drilled to receive a pin to lock the toggle arm 5 and prevent it rocking over to the other side of the frame when the points are operated.

It is preferred that the link 8 should be a little longer than the toggle arm 5 in order to cause the parts to be thrown when the bell crank frame 1 is a little past the center of its movement. The longer the link is made the farther must the crank frame be turned to cause the toggle arm 5 to shoot over, or, in other words, a longer link means a greater angle through which the crank frame must be turned to secure superimposition of the toggle arm 5 and link 8.

In some cases, the toggle mechanism may comprise a spring.

Figs. 4C and 5 show an arrangement where a spring 15 is substituted for the toggle arm 5. It comprises a box or casing 14: for the reception of pivot pins 2 carried by brackets 16 on the plate 1. Que end of the link 8 is connected by a pin 10 to the shouldered head 11 of a plunger 6 having a tail piece arranged to work in a socket piece '7 seated to rock in the frame 1. The spring 15 reacts between the socket piece 7 and shoul dered head 11. The link 8 is connected by a pin 13 to an anchor bolt 9 provided with nuts for adjusting purposes.

As before, 4 are the holes for connection to the point rigging and 12 are holes for converting the mechanism into a oneway acting apparatus. 17 represent rods by which the plate 1 can be operated otherwise than through the points.

In Fig. 6 the arrangement only differs materially from that of Fig. i in that the stationary pivot for the link 8 is disposed between the pivot 2 and the pivotal connection between the link 8 and the spring member 15 which connection is shown as constituted by an adjusting screw 18. In this case angular movement of the link 8 is limited as by stops 19, 20 upon the framing 1a. In Fig. 7 the crank lever 1 is replaced by a point rod.

What I claim is l. The combination with a railway point and a load adapted to hold such point in either of two extreme positions of an articulated link mechanism which as a whole has no dead center and through which the load is transmitted to the point.

2. A mechanism comprising a device, such as a point, to be moved to two extreme positions, and a pivot following the movements of the device and pursuing an arcuate path, a member connected at one end to such pivot, a second pivotal member articulated to the opposite end of the first named member and adapted to exert a turning effort upon the latter in opposite senses at different times, means subjecting the articulated members to a load tending to alter the angle between them and means acting in conjunction with the device to be moved to prevent further alteration of the angle between the articulated members when the said device is in either of its extreme positions, the connection of the articulated members to the device to be moved being such that the members assume a dead center relationship only while the line representing its direction is inclined to the line representing infinite resistance to the load, substantially as described.

3. A mechanism comprising a device, such as a point, to be moved to two extreme positions, a pair of articulated members, and means subjecting such members to a load tending to separate them, one member of the said pair of members being pivoted to the device to be moved and provided with stops and the other member being connected to a pivot movable with the load, the arrangement being such that after the member connected to the load has been moved through a certain distance it is caused to abruptly engage one stop of the companion member and impart movement to the latter through such stop, the mechanism as a whole having no dead center.

4. A mechanism comprising a device to be moved about a pivot, a member pivotally connected thereto and limited as to angular movement relatively to the device, a second member pivoted to the opposite end of the first named member, and means subjecting the connected members to a load tending to separate them.

5. A mechanism comprising a device to be moved about a pivot, a spring-extensible member pivotally secured thereto and limited as to angular movement relatively to the device, and a rigid member, pivoted to the opposite end of the extensible member and movable about a stationary pivot, the pivot connecting the two members being disposed to one side of a line joining the center of the device to be moved and the stationary pivot aforesaid while the pivotal connection between the device to be moved and the extensible member is disposed at the opposite side of the line in one extreme position and vice versa.

6. A mechanism comprising a device to be moved, a spring-extensible member pivotally connected thereto, and a rigid member pivoted to the opposite end of the extensible member the arrangement being such that the said members are capable of moving angular-1y one in relation to the other at a certain time without moving the device to be moved, substantially as described.

7 A mechanism comprising a device to be moved and having a pivot following an arcuate path when the device moves, a member connected at one end to such pivot, stops upon the said device adapted to limit the movement of said member in relation thereto, a companion member pivoted to the first named member, and a load acting upon said connected members, the arrangement being such that after the device has moved through a certain distance the member pivotally connected thereto is free to move independently of the device abruptly from one limit stop to the other and hence to influence movement of the device by momentum added to the load, the mechanism as a whole having no dead center.

8. A mechanism comprising a device to be moved and having a pivot following an arcuate path when the device moves, a spring-extensible member connected at one end to such pivot, stops upon the said device adapted to limit the movement of said memher in relation thereto, and a rigid member pivoted to the first named member, the arrangement being such that after the device has moved through a certain distance the extensible member is free to move independ ently of the device abrutly from one limit stop to the other and hence to influence movement of the device by momentum added to the spring force, the mechanism as a whole having no dead center.

9. A mechanism comprising a device, such as a point, to be moved to two extreme positions, and a pivot translated with such member, a member connected at one end to such pivot, a second pivotal member articulated to the opposite end of the first named memher and adapted to exert a turning efliort upon the latter in opposite senses at difi'erent times, means subjecting the articulated members to a load tending to alter the angle between them and means adapted to prevent further alteration of the angle between the articulated members when the device to be moved is in either of the extreme positions, the connection of the articulated members to the device to be moved being such that the mechanism as a whole has no dead center.

Signed at London, England, this 18th day of March 1913.

HUGH ALEXANDER THOMSON- lVitnesses VILLIAM Cnoss, ARTHUR F. BURGESS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

Washington, D. C. 

